The primary findings of the public inquiry, based on data recovered from the flight data recorders, were that the crash resulted from a deep stall caused by the captain failing to maintain the correct airspeed and configure the aircraft’s high-lift devices correctly, and that the crew failed to monitor the airspeed and aircraft configuration. Secondary factors included pilot incapacitation and the low experience level of the co-pilot. The process and findings of the inquiry were considered highly controversial among British pilots and the public.

Recommendations from the inquiry led to the mandatory installation of cockpit voice recorders in British-registered airliners. Another recommendation was for greater caution before allowing off-duty flight crew members to occupy flight deck seats.

Industrial relations background

The International Federation of Air Line Pilots’ Associations (IFALPA) had declared Monday 19 June 1972 (the day after the accident) as a worldwide protest strike against aircraft hijacking which had become commonplace in the early 1970s. Support was expected, but the British Air Line Pilots Association (BALPA) nevertheless organised a confidential postal ballot to ask its members at BEA whether or not they wanted to strike. Because of the impending strike action, air travellers had amended their plans to avoid disruption, and as a result Flight BE 548 was full, despite the service operating on a Sunday, traditionally a day of light travel.

BALPA was also in an industrial dispute with BEA, concerning issues of pay and working conditions. The dispute was highly controversial, with those in favour being mainly younger pilots, and those against mostly older pilots. A group of 22 BEA Trident co-pilots known as Supervisory First Officers (SFOs) were already on strike, citing their low status and high workload. To facilitate the further training of a number of newly-qualified co-pilots, SFOs were instructed to occupy only the third flight deck seat of the Trident and to act in the capacity known as “P3”, involving operating the aircraft’s systems and assisting the captain (known as “P1” on the BEA Trident fleet) and the co-pilot (known as “P2”) who between them handled the aircraft. In other airlines and aircraft, the job of BEA Trident SFO/P3s was usually performed by flight engineers. As a result of being limited to the P3 role, BEA Trident SFOs/P3s were denied experience of aircraft handling, a measure which led to loss of pay, which they resented. In addition, their status led to a regular anomaly: experienced SFO/P3s could only assist while less-experienced co-pilots actually flew the aircraft.

Captain Key’s outburst

Tensions and hazards resulting from the positions in which BEA Trident SFOs and young co-pilots were placed came to a head shortly before the accident. On Thursday 15 June, a captain complained vociferously that the inexperienced co-pilot whom he had been assigned “would be useless in an emergency”. Upset, the co-pilot committed a serious error on departure from Heathrow. The mistake was noted and remedied by the SFO, who later related the event to his colleagues as an example of avoidable danger. This event became known among BEA pilots as the “Dublin Incident”.

A mere hour and a half before the departure of BE 548, its rostered captain, Stanley Key, was involved in a quarrel in the BEA crew room at Heathrow’s Queen’s Building with a First Officer named Flavell. The subject of Key’s outburst was the threatened strike which Flavell supported and Key opposed. Both of Key’s flight deck crew members on BE 548 witnessed the altercation, and another bystander described Key’s outburst as “the most violent argument he had ever heard”. Shortly afterwards Key apologised to Flavell, and the matter seemed closed. Key’s robustly anti-strike views had won him enemies in the weeks before the accident, and graffiti directed personally against him had appeared on the flight decks of BEA Tridents, including Papa India. The graffiti found on Papa India’s P3 desk was analysed by a handwriting expert during the investigation to determine who might have written it, but this could not be determined and the public inquiry members eventually dismissed it as irrelevant.

Operational background

The aircraft operating Flight BE 548 was a Hawker Siddeley Trident Series 1 short- to medium-range three-engined airliner. This particular Trident was one of twenty-four de Havilland DH.121s ordered by BEA in 1959, and with the constructor’s number 2109 it was registered to the corporation as G-ARPI in 1961. By the time of the aircraft’s first flight on the 14 April 1964 the company had become Hawker Siddeley Aviation, and Papa India was delivered to BEA on 2 May 1964.

Diagrammatic representation of a deep stall

While technically advanced, the Trident (and other aircraft with a T-tail arrangement) had potentially dangerous stalling characteristics. If its airspeed was insufficient, and particularly if its high-lift devices were not extended at the low speeds typical of climbing away after take-off or of approaching to land, it could enter a deep stall (or “superstall”) condition from which recovery was practically impossible.

The danger first came to light in a near-crash during a 1962 test flight when de Havilland pilots Peter Bugge and Ron Clear were testing the Trident’s stalling characteristics by pitching its nose progressively higher, thus reducing its airspeed: “After a critical angle of attack was reached, the Trident began to sink tail-down in a deep stall.” Eventually it entered a flat spin, and a crash “looked inevitable”, but luck saved the test crew. The incident resulted in the Trident being fitted with an automatic stall warning system known as a “stick shaker“, and a stall recovery system known as a “stick pusher” which automatically pitched the aircraft down in order to build up speed if the crew failed to respond to the warning.

These systems were the subject of “one of the most comprehensive stall programmes on record”, involving some 3,500 stalls being performed by Hawker Siddeley before the matter “was squared off to the satisfaction of … the ARB” (Air Registration Board). The stall warning and recovery systems tended to over-react: of ten activations between the Trident entering service and June 1972, only half were genuine, although there had been no false in-flight activations. BEA Trident pilots were questioned informally by one captain, over half of them said that they would disable the protection systems on activation, rather than let them recover the aircraft to a safe attitude. Random checks carried out by the airline after the accident showed that this was not the case; 21 captains stated that they had witnessed their co-pilots react correctly to any stall warnings.

Accident synopsis

Departure

The flight crew boarded BE 548 (call signBealine 548) at 15:20 to prepare for a 15:45 departure. The crew comprised Captain Stanley Key as P1, Second Officer Jeremy Keighley as P2 and Second Officer Simon Ticehurst as P3. The captain was 51 and had accumulated 15,000 flying hours experience, of which 4,000 were on Tridents. Keighley was 22 and had joined line flying a month and a half earlier, with 29 hours as P2. Ticehurst was 24 and had over 1,400 hours, including 750 hours on Tridents.

Among the passengers were 29 Americans, 29 Belgians, 28 Britons, 12 Irish, four South Africans and three Canadians. There was also one passenger from each of French West Africa, India, Jamaica, Latin America, Nigeria and Thailand. There were between 25 and 30 women passengers and several children on board.

At 15:36 flight dispatcher J Coleman presented the load sheet to Key whose request for engine start clearance was granted three minutes later. As the doors were about to close, Coleman asked Key to accommodate a BEA flight crew which had to collect a Merchantman aircraft from Brussels. The additional weight of the three crew members necessitated the removal of a quantity of mail and freight from the Trident to ensure its total weight (less fuel) did not exceed the permitted maximum of 41,730 kg. This was exceeded by 24 kg, but as there had been considerable fuel burnoff between startup and takeoff, the total aircraft weight (including fuel) was within the maximum permitted take-off weight.

The “dead-heading” crew was led by Captain John Collins, an experienced former Trident First Officer, who was allocated the observer’s seat on the flight deck. One seat, occupied by a baby, was freed by the mother holding it in her arms.

Final flight path of BEA Flight 548; red numbers are times in seconds past brake release.

The doors closed at 15:58 and at 16:00 Key requested pushback. At 16:03 BE 548 was cleared to taxi to the holding point adjacent to the start of Runway 27 Right. During taxi, at 16:06 the flight received its departure route clearance: a routing known as the “Dover One Standard Instrument Departure”. This Standard Instrument Departure involved taking-off to the west over the Instrument Landing Systemlocaliser and middle marker beacon of the reciprocal Runway 09 Left, turning left to intercept the 145° bearing to the EpsomNon-Directional Beacon (NDB) (to be passed at 3,000 feet (910 m) or more), and then proceeding to Dover. Key advised the tower that he was ready for take-off and was cleared to do so. He subsequently reported an unspecified technical problem and remained at the holding point for two minutes to resolve it.

At 16:08 Key again requested and received take-off clearance. A cross wind was blowing from 210° at 17 knots (31 km/h). Conditions were turbulent, with driving rain and a low cloud base of 1,000 feet (300 m); broken cloud was also reported at 600 feet (180 m). At 16:08:30, BE 548 began its take-off run which lasted 44 seconds, the aircraft leaving the ground at an indicated airspeed (IAS) of 145 knots (269 km/h). The safe climb speed (V2) of 152 knots (282 km/h) was reached quickly, and the undercarriage was retracted. After 19 seconds in the air the autopilot was engaged at 355 feet (108 m) and 170 knots (310 km/h); the autopilot’s airspeed lock was engaged even though the actual required initial climb speed was 177 knots (328 km/h).

At 16:09:44 (74 seconds after the start of the take-off run), passing 690 feet (210 m), Key commenced the turn towards the Epsom NDB and reported that he was climbing as cleared and the flight entered cloud. At 16:10 (90 seconds), Key commenced a standard noise abatement procedure which involved reducing engine power. As part of this, at 16:10:03 (93 seconds) he retracted the flaps from their take-off setting of 20°. Shortly afterwards, BE 548 reported passing 1,500 feet (460 m) above ground level and was re-cleared to climb to 6,000 feet (1,800 m) above sea level. During the turn, the airspeed decreased to 157 knots (291 km/h), 20 knots (37 km/h) below the target speed.

Stall warnings

At 16:10:24 (114 seconds), the leading edge devices were selected to be retracted at a height above the ground of 1,770 feet (540 m) and a speed of 162 knots (300 km/h); 63 knots (117 km/h) below the safe droop-retraction speed of 225 knots (417 km/h). One second afterwards, visual and audible warnings of a stall activated on the flight deck, followed at 16:10:26 hrs (116 seconds) by a stick shake and at 16:10:27hrs (117 seconds) by a stick push which disconnected the autopilot, in turn activating a loud autopilot disconnect warning horn that continued to sound for the remainder of the flight. Key levelled the wings but held the aircraft’s nose up, which kept the angle of attack high, further approaching a stall.

T-tail and retracted leading edge devices of a Hawker Siddeley Trident

By 16:10:32 (122 seconds), the leading edge devices had stowed fully into the wing. The speed was 177 knots (328 km/h), and height above the ground was 1,560 feet (480 m), with the aircraft still held into its usual climb attitude. Key continued to hold the nose-up attitude when there was a second stick shake and stick push in the following two seconds. A third stick push followed 127 seconds into the flight but no recovery was attempted. One second later, the stall warning and recovery system was overridden by a flight crew member.

At 16:10:39 (129 seconds), the aircraft had descended to 1,275 feet (389 m) and accelerated to 193 knots (357 km/h) as a result of the stall recovery system having pitched the aircraft’s nose down to increase airspeed. G-ARPI was in a 16° banked turn to the right, still on course to intercept its assigned route. Key pulled the nose up once more to reduce airspeed slightly, to the normal ‘droops extended’ climb speed of 177 knots (328 km/h), but this further stalled the aircraft.

At 16:10:43 (133 seconds), the Trident entered a deep stall. It was descending through 1,200 feet (370 m), its nose was pitched up by 31°, and its airspeed had fallen below the minimum indication of 54 knots (100 km/h). At 16:10:55 (145 seconds) and 1,000 feet (300 m), the Trident was descending at 4,500 feet per minute (23 m/s). Impact with the ground came at 16:11 precisely, 150 seconds after brake release.

The aircraft just cleared high-tension overhead power lines and came to rest on a narrow strip of land surrounded by tall trees immediately south of the A30 road, and a short distance south of the King George VI Reservoir near the town of Staines.There was no fire on impact; however, one broke out during the rescue effort when cutting apparatus was used.

Eyewitnesses and rescue operations

There were three eyewitnesses to the impact; two brothers, Paul and Trevor Burke, aged 9 and 13, who were walking nearby, and a passing motorist who stopped and called at a house to telephone the airport authorities and advise them of the accident.

We were out with the dog and I looked up and saw the plane. It was just coming out of the mist when the engines stalled and it seemed it glided down. It was just like a dream. The plane just fell out of the sky. We just about saw it hit the ground … because it was right in a clump of trees. When it did hit the ground the front bit hit first and the back bit was just blown away.

—Trevor Burke, Air Disasters

Air traffic controllers had not noticed the disappearance from radar of BE 548, while the emergency services only became aware of the accident after 15 minutes had passed and did not know the precise circumstances of it for nearly an hour. First on the scene of the accident was a nurse who lived nearby, who had been alerted by the two boys, and an ambulance crew that happened to be driving past by chance. A male passenger who had survived the accident was discovered in the aircraft cabin, but died without recovering consciousness on arrival at Ashford Hospital. A young girl was also found alive but died at the scene; there were no other survivors. Altogether, 30 ambulances and 25 fire engines attended the accident.

Sensation-seeking occupants of cars formed heavy traffic jams soon after, and were described by Minister of Aerospace Michael Heseltine on BBC Television that evening as “Ghouls, unfortunate ghouls”. However the crash site was sufficiently inaccessible for the police to successfully control spectators, and contemporary reports that members of the public impeded rescue services by their presence near the site were dismissed during the subsequent inquiry.

A BEA Captain, Eric Pritchard, arrived at the accident scene shortly after the bodies had been removed, he noted the condition of the wreckage and drew his own early conclusions:

The aircraft had impacted in a high nose up attitude. The No. 2 engine had dug a considerable crater. The tail section was almost if not completely separated from the rest of the airframe. There was little evidence of any forward movement, in fact, the complete aircraft looked intact though distorted and broken, mainly the fuselage. Both wings suffered not much visible damage. I noticed that the droops and flaps were retracted.

—Eric Pritchard, Disasters In The Air

The accident became known as the Staines disaster, and was the worst air disaster in Britain prior to the Pan Am Flight 103 bombing over Lockerbie, Scotland in 1988. The crash was also the first aviation disaster to occur in the United Kingdom involving the loss of more than 100 lives.

Investigation and public inquiry

On Monday 19 June 1972 Michael Heseltine announced to the British Parliament that he had directed a Court of Inquiry, an ad hoc tribunal popularly called a “public inquiry“, to investigate and report on the accident. Public inquiries bypassed the usual British practice whereby the Accidents Investigation Branch (AIB) investigated and reported on air crashes, and were held only in cases of acute public interest. On 14 July, the High Court Judge Sir Geoffrey Lane was appointed to preside over the inquiry as Commissioner.

The British aviation community was wary of public inquiries for several reasons. In such inquiries, AIB inspectors were on an equal footing with all other parties, and the ultimate reports were not drafted by them, but by the Commissioner and his or her Assessors. Proceedings were often adversarial, with counsel for victims’ families regularly attempting to secure positions for future litigation, and deadlines were frequently imposed on investigators. Pressure of work caused by the Lane Inquiry was blamed for the death of a senior AIB inspector who committed suicide during the inquiry.

The pathologist stated that Captain Key had a pre-existing heart condition, atherosclerosis, and had suffered a potentially distressing arterial event caused by raised blood pressure typical of stress. (This event was popularly interpreted by the public as a heart attack.) It had taken place “not more than two hours before the death and not less than about a minute” according to the pathologist’s opinion given as evidence during the public inquiry. In other words, Key could have suffered it at any time between the row in the crewroom and 90 seconds after the start of the take-off run or the instant of commencing noise abatement procedures. The pathologist could not specify the degree of discomfort or incapacitation which Key might have felt. The Captain’s medical state continued to be the subject of “conflicting views of medical experts” throughout the inquiry and beyond.

Lane Inquiry

The public inquiry, known as the “Lane Inquiry”, opened at the Piccadilly Hotel in London on 20 November 1972, and continued for 37 business days until 25 January 1973 despite expectations that it would end sooner. It was opened by Geoffrey Wilkinson of the AIB with a description of the accident, and counsel for the relatives of the crew members and passengers then presented the results of their private investigations. In particular, Lee Kreindler of the New York City Bar presented claims and arguments which were considered tendentious and inadmissible by pilots and press reporters. They involved hypotheses about the mental state of Captain Key, conjecture about his physical state (Kreindler highlighted disagreements between US and British cardiologists) and allegations about BEA management. The allegations were delivered using tactics considered as “bordering on the unethical”. The inquiry also conducted field inspections, flew in real Tridents and “flew” the BEA Trident simulator as well as observing the Hawker Siddeley Trident control systems rig. Its members visited the reassembled wreckage of G-ARPI at Farnborough and were followed by the press throughout their movements. The bare facts being more-or-less uncovered soon after the event, the inquiry was frustrated by the absence on the accident aircraft of a cockpit voice recorder.

The stall warning and stall recovery systems were at the centre of the inquiry, which examined in some detail their operation and why the flight crew might have overridden them. A three-way air pressure valve (part of the stall recovery system) was found to have been one-sixth of a turn out of position, and the locking wire which secured it was missing. Calculations carried out by Hawker Siddeley determined that if the valve was in this position during the flight then the reduction in engine power for the noise abatement procedure may well have activated the warning light that indicated low air pressure in the system. The failure indications might have appeared just prior to take-off and could have accounted for the two-minute delay at the end of the runway.A captain who had flown Papa India on the morning of the accident flight noted no technical problems, and the public inquiry found that the position of the valve had no significant effect on the system.

The inquiry’s findings as to the main causes of the accident, were that:

The captain failed to maintain the recommended airspeed.

The leading edge devices were retracted prematurely.

The crew failed to monitor airspeed and aircraft configuration.

The crew failed to recognise the reasons for the stall warnings and stall recovery system operation.

The crew wrongly disabled the stall recovery system.

Underlying causes of the accident were also identified:

Captain Key was suffering from a heart condition.

The presence of Captain Collins on the flight deck may have been a distraction.

There was a lack of crew training on how to manage pilot incapacitation.

The low flying experience level of Second Officer Keighley.

Apparent crew unawareness on the effects of an aircraft configuration change.

Unawareness of the crew regarding the stall protection systems and the cause of the event.

The absence of a baulk mechanism to prevent droop retraction at too low an airspeed.

Recommendations included an urgent call for cockpit voice recorders and for closer cooperation between the Civil Aviation Authority and British airlines. Though the report covered the state of industrial relations at BEA, no mention was made of it in its conclusions, despite the feelings of observers that it intruded directly and comprehensively onto the flight deck of the stricken aircraft. BEA ceased to exist as a separate entity in 1974, when it and British Overseas Airways Corporation merged to form British Airways. A recommendation of the report that all British-registered civil passenger-carrying aircraft of more than 27,000 kg (60,000 lb) all-up weight should be equipped with cockpit voice recorders resulted in their fitting becoming mandatory on larger British-registered airliners from 1973.

One issue treated as secondary at the inquiry was the presence on the flight deck observer’s seat of Captain Collins. The Lane report recommended greater caution in allowing off-duty flight crew members to occupy flight deck seats, and aired speculation that Collins might have been distracting his colleagues.Sources close to the events of the time suggest that Collins played an altogether more positive role by attempting to lower the leading edge devices in the final seconds of the flight.

There were protests at the conduct of the inquiry by BALPA (which likened it to “a lawyers’ picnic”), and by the Guild of Air Pilots and Air Navigators which condemned the rules of evidence adopted and the adversarial nature of the proceedings. Observers also pointed to an unduly favourable disposition by the inquiry to Hawker Siddeley, manufacturer of the Trident, and to the makers of the aircraft’s systems. Debate about the inquiry continued throughout 1973 and beyond.

The accident led to a much greater emphasis on crew resource management training, a system of flight deck safety awareness that remains in use today.

A group of 16 doctors and senior staff from the Royal London Homeopathic Hospital were also on board the flight, and a memorial bench to them can be found close to Great Ormond Street Hospital in Queen Square.

Coming back from the JCI European Conference in Edinburgh, there was a group of 7 members of JCI Belgium, together with 2 partners who were killed. The JCI Staines Foundation was established, supporting the families and children of the members that never reached Brussels.

Memorials

Two memorials to the crew and passengers were dedicated on 18 June 2004 in Staines.

The first is a stained glass window in St Mary’s church, Church Street. The second is a slightly more accessible area of reflection with seating on the Moormede estate, close to where the accident occurred. The memorial is in the park/play area near the end of Waters Drive in the Moormede Estate.